Why is coparenting so hard to comprehend?

I honestly don’t understand why it is so hard for people to coparent. When you have a child and chose to no longer be in a relationship with the other parent(no matter the reason) you then forfeit your right to be involved 24/7 with your child. Your child will now have time with you and time with with other parent. You will have to share responsibilities for the child and communicate to make decisions for that child. Even if you can not stand the other parent, you have to put that aside and do what you need to do to make sure your child is taken care of. Put your personal hatred and feelings on the back burner and put your child’s needs first. Go to the school events and daycare parties and celebrate with your child. Respect the other parent at these events. Set an example for your child on how they should treat the other parent of their child in their future. Teach them how to respectfully exist in the presence of others they disagree with. Teach your child how to expect to be treated by others no matter the difference in opinion. Show your child that although you and their other parents no longer chose to he together, it is perfectly acceptable for them to love and want to he will both their parents. Teach your child that they can love themselves and that they were created out of love, regardless of the fact that their parents are no longer together. For the love of God, STOP teaching your child to hate a part of themselves because they came from both of your and when you shiw them how mich you hate their other parent, it teaches them to hate part of who they are and where they came from.